{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,4]],"date-time":"2026-11-04T04:26:47Z","timestamp":1793766407572,"version":"4.6.1"},"reference-count":52,"publisher":"Wildlife Disease Association","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Wildlife Diseases"],"published-print":{"date-parts":[[2026,11,4]]},"abstract":"<jats:p>The Guadalupe fur seal (GFS; Arctocephalus townsendi) is susceptible to the ecologic impacts of anomalous ocean warming events, which have led to prey scarcity that, in turn, affects its feeding habits, nutritional condition, and survival at Guadalupe Island, Mexico. Concurrently, ocean warming has also caused increased outbreaks of zoonotic diseases in North Pacific pinnipeds. This study assessed the exposure to zoonotic disease agents (Leptospira spp., Sarcocystis neurona, and Toxoplasma gondii) in GFS on Guadalupe Island (2016, 2017, and 2020), during a period of persistent ocean warming and unusual strandings in Mexico and the USA. Blood samples were collected from 129 GFS (82 females and 47 males) at Guadalupe Island. All tested GFS were seronegative for Leptospira spp. and S. neurona, whereas 17\/129 (13%) tested seropositive for T. gondii, predominantly pups (1 yr) of both sexes. Although T. gondii was only detected in a relatively small proportion of GFS at Guadalupe Island, the parasite is frequently reported in pinniped populations inhabiting coastal ecosystems worldwide. Currently, the GFS population is increasing, which may promote range expansion and increase interaction with other marine mammals that may carry zoonotic pathogens along the coastal ecosystems of the northeastern Pacific Ocean. Only GFS pups were seropositive for T. gondii, which may reflect a passive transfer of maternal antibodies during lactation. However, the low prevalence observed may also indicate limited environmental exposure or other ecologic factors. As on other islands, exotic invasive species are reported in Guadalupe Island, which cannot be discounted as a possible source of exposure of GFS to pathogens and parasites, such as T. gondii.<\/jats:p>","DOI":"10.7589\/jwd-d-25-00167","type":"journal-article","created":{"date-parts":[[2026,11,4]],"date-time":"2026-11-04T04:07:52Z","timestamp":1793765272000},"page":"829-838","source":"Crossref","is-referenced-by-count":0,"title":["SEROLOGIC INVESTIGATION OF LEPTOSPIRA SPP., SARCOCYSTIS NEURONA, AND TOXOPLASMA GONDII IN GUADALUPE FUR SEALS (ARCTOCEPHALUS TOWNSENDI) FROM GUADALUPE ISLAND, MEXICO"],"prefix":"10.7589","volume":"62","author":[{"given":"Miriam E.","family":"Romero-Vel\u00e1zquez","sequence":"first","affiliation":[{"name":"Instituto Polit\u00e9cnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Polit\u00e9cnico Nacional s\/n Colonia Playa Palo de Santa Rita, La Paz, Baja California Sur 23096, M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cara L.","family":"Field","sequence":"additional","affiliation":[{"name":"The Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Casandra","family":"G\u00e1lvez","sequence":"additional","affiliation":[{"name":"Instituto Polit\u00e9cnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Polit\u00e9cnico Nacional s\/n Colonia Playa Palo de Santa Rita, La Paz, Baja California Sur 23096, M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tenaya","family":"Norris","sequence":"additional","affiliation":[{"name":"The Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rodrigo","family":"Moncayo-Estrada","sequence":"additional","affiliation":[{"name":"Instituto Polit\u00e9cnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Polit\u00e9cnico Nacional s\/n Colonia Playa Palo de Santa Rita, La Paz, Baja California Sur 23096, M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xchel G.","family":"Moreno-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Instituto Polit\u00e9cnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Polit\u00e9cnico Nacional s\/n Colonia Playa Palo de Santa Rita, La Paz, Baja California Sur 23096, M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fernando R.","family":"Elorriaga-Verplancken","sequence":"additional","affiliation":[{"name":"Instituto Polit\u00e9cnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Polit\u00e9cnico Nacional s\/n Colonia Playa Palo de Santa Rita, La Paz, Baja California Sur 23096, M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"4415","reference":[{"key":"1","doi-asserted-by":"crossref","unstructured":"K Acevedo-Whitehouse, H De la Cueva, FMD Gulland, et al.  \"J Wildl Dis.\"  39, \"Evidence of Leptospira interrogans infection in California sea lion pups from the Gulf of California.\" 145 (2003)","DOI":"10.7589\/0090-3558-39.1.145"},{"key":"2","unstructured":"A Aguirre-Mu\u00f1oz, A Samaniego-Herrera, L Luna-Mendoza, et al.  \"Island invasives: Eradication and management.\"  \"Island restoration in Mexico: Ecological outcomes after systematic eradications of invasive mammals.\" 542 (2011)"},{"key":"3","doi-asserted-by":"crossref","unstructured":"E Ahmadpour, MT Rahimi, A Ghojoghi, et al.  \"Acta Parasitol.\"  67, \"Toxoplasma gondii infection in marine animal species, as a potential source of food contamination: A systematic review and meta-analysis.\" 592 (2022)","DOI":"10.1007\/s11686-021-00507-z"},{"key":"4","doi-asserted-by":"crossref","unstructured":"C Alvarado-Esquivel, R S\u00e1nchez-Okrucky, JP Dubey,  \"Vet Parasitol.\"  184, \"Serological evidence of Toxoplasma gondii infection in captive marine mammals in Mexico.\" 321 (2012)","DOI":"10.1016\/j.vetpar.2011.08.036"},{"key":"5","doi-asserted-by":"crossref","unstructured":"MJ Amador-Capitanachi, XG Moreno-S\u00e1nchez, PD Ventura-Dom\u00ednguez, et al.  \"Mar Mamm Sci.\"  36, \"Ecological implications of unprecedented warm water anomalies on interannual prey preferences and foraging areas of Guadalupe fur seals.\" 1254 (2020)","DOI":"10.1111\/mms.12718"},{"key":"6","doi-asserted-by":"crossref","unstructured":"M Banuet-Mart\u00ednez, W Espinosa-de-Aquino, FR Elorriaga-Verplancken, et al.  \"PLoS One.\"  12, \"Climatic anomaly affects the immune competence of California sea lions.\" e0179359 (2017)","DOI":"10.1371\/journal.pone.0179359"},{"key":"7","doi-asserted-by":"crossref","unstructured":"L Barbosa, B Borremans, AC Deming, et al.  \"Mar Mamm Sci.\"  40, \"Inhalant anesthesia for minimally invasive procedures in free-ranging Guadalupe fur seals (Arctocephalus philippii townsendi).\" e13124 (2024)","DOI":"10.1111\/mms.13124"},{"key":"12","doi-asserted-by":"crossref","unstructured":"AM Colagross-Schouten, JAK Mazet, FMD Gulland, et al.  \"J Wildl Dis.\"  38, \"Diagnosis and seroprevalence of leptospirosis in California sea lion from coastal California.\" 7 (2002)","DOI":"10.7589\/0090-3558-38.1.7"},{"key":"14","doi-asserted-by":"crossref","unstructured":"E D'Agnese, D Lambourn, J Rice, et al.  \"Mar Mamm Sci.\"  36, \"Reemergence of Guadalupe fur seals in the U.S. Pacific Northwest: The epidemiology of stranding events during 2005\u20132016.\" 828 (2020)","DOI":"10.1111\/mms.12678"},{"key":"15","doi-asserted-by":"crossref","unstructured":"Vaishali Deepak, R Gupta, VJ Jadhav, et al.  \"Int J Livest Res.\"  9, \"Pinniped zoonoses: A review.\" 1 (2019)","DOI":"10.5455\/ijlr.20190730064613"},{"key":"17","doi-asserted-by":"crossref","unstructured":"A Duarte-Benvenuto, C Sacrist\u00e1n, L Reisfeld, et al.  \"J Wildl Dis.\"  58, \"Clinic-pathologic findings and pathogen screening in fur seals (Arctocephalus australis and Arctocephalus tropicalis) stranded in southeastern Brazil, 2018.\" 86 (2022)","DOI":"10.7589\/JWD-D-21-00060"},{"key":"19","doi-asserted-by":"crossref","unstructured":"FR Elorriaga-Verplancken, T Norris, K Acevedo-Whitehouse, et al.  \"Ecology and conservation of pinnipeds in Latin America.\"  \"Guadalupe fur seal (Arctocephalus philippii townsendi, Brunner 2004).\" 77 (2021a)","DOI":"10.1007\/978-3-030-63177-2_5"},{"key":"20","doi-asserted-by":"crossref","unstructured":"FR Elorriaga-Verplancken, A Paniagua-Mendoza, CJ Hern\u00e1ndez-Camacho, et al.  \"Aquat Mamm.\"  47, \"A new Guadalupe fur seal colony in the Gulf of California? 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Hubbs,  \"Zoonooz.\"  29, \"The Guadalupe fur seal still lives\" 6 (1956)"},{"key":"28","doi-asserted-by":"crossref","unstructured":"G Jankowski, MJ Adkesson, JT Saliki, et al.  \"J Zoo Wildl Med.\"  46, \"Survey for infectious disease in the South American fur seal (Arctocephalus australis) population at Punta San Juan, Per\u00fa.\" 246 (2015)","DOI":"10.1638\/2014-0120.1"},{"key":"30","doi-asserted-by":"crossref","unstructured":"A Ju\u00e1rez-Ruiz, MA Pardo, J Hern\u00e1ndez-Montoya, et al.  \"ICES J Mar Sci.\"  79, \"Guadalupe fur seal pup production predicted from annual variations of sea surface temperature in the southern California Current Ecosystem.\" 1637 (2022)","DOI":"10.1093\/icesjms\/fsac097"},{"key":"31","doi-asserted-by":"crossref","unstructured":"H Katz, F Schelotto, D Bakker, et al.  \"Dis Aquat Org.\"  150, \"Survey of selected pathogens in free-ranging pinnipeds in Uruguay.\" 69 (2022)","DOI":"10.3354\/dao03676"},{"key":"32","doi-asserted-by":"crossref","unstructured":"SA Lindsay, CGB Caraguel, R O'Handley, et al.  \"Front Mar Sci.\"  9, \"Toxoplasma gondii seroprevalence in the endangered Australian sea lion (Neophoca cinerea).\" 965865 (2022)","DOI":"10.3389\/fmars.2022.965865"},{"key":"33","unstructured":"L Luna-Mendoza, JM Barredo-Barberena, JC Hern\u00e1ndez-Montoya, et al.  \"Island invasives: Eradication and management.\"  \"Planning for the eradication of feral cats on Guadalupe Island, Mexico: Home range, diet, and bait acceptance.\" 192 (2011)"},{"key":"36","doi-asserted-by":"crossref","unstructured":"MA Miller, IA Gardner, C Kreuder, et al.  \"Int J Parasitol.\"  32, \"Coastal freshwater runoff is a risk factor for Toxoplasma gondii infection of southern sea otters (Enhydra lutris nereis).\" 997 (2002a)","DOI":"10.1016\/S0020-7519(02)00069-3"},{"key":"37","doi-asserted-by":"crossref","unstructured":"MA Miller, IA Gardner, A Packham, et al.  \"J Parasitol.\"  88, \"Evaluation of an indirect fluorescent antibody test (IFAT) for demonstration of antibodies to Toxoplasma gondii in the sea otter (Enhydra lutris).\" 594 (2002b)","DOI":"10.2307\/3285456"},{"key":"39","unstructured":"TA Norris  and FR Elorriaga-Verplancken  \"Guadalupe fur seal population census and tagging in support of marine mammal monitoring across multiple Navy training areas in the Pacific Ocean, 2019\u20132020.\"  (2020)"},{"key":"42","doi-asserted-by":"crossref","unstructured":"L Reisfeld, C Sacrist\u00e1n, E Ferreira-Machado, et al.  \"Dis Aquat Org.\"  136, \"Toxoplasmosis and Sarcocystis spp. infection in wild pinnipeds of the Brazilian coast.\" 235 (2019)","DOI":"10.3354\/dao03410"},{"key":"43","doi-asserted-by":"crossref","unstructured":"C Rengifo-Herrera, LM Ortega-Mora, G \u00c1lvarez-Garc\u00eda, et al.  \"Vet Parasitol.\"  190, \"Detection of Toxoplasma gondii antibodies in Antarctic pinnipeds.\" 259 (2012)","DOI":"10.1016\/j.vetpar.2012.05.020"},{"key":"44","unstructured":"E Rojas-Sanchez, CL Field, A Packham, et al.  \"Proceedings of the Wildlife Disease Association Conference, Wildlife Disease Association, Victoria, British Columbia, Canada 27 July\u20131 August.\"  \"Validation of an indirect fluorescent antibody test for Sarcocystis neurona infection in California sea lions.\" (2025)"},{"key":"45","doi-asserted-by":"crossref","unstructured":"A S\u00e1nchez, A Contreras, JC Corrales, et al.  \"SESPAS Report 2022. 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Ziehl-Quir\u00f3s,  \"Prevalencia de cuatro enfermedades infecciosas en lobo fino en Isla Guadalupe, M\u00e9xico.\"  77 (2015)"},{"key":"52","doi-asserted-by":"crossref","unstructured":"EC Ziehl-Quir\u00f3s, MC Garc\u00eda-Aguilar, E Mellink,  \"Dis Aquat Org.\"  122, \"Colony-level assessment of Brucella and Leptospira in the Guadalupe fur seal, Isla Guadalupe, Mexico.\" 185 (2017)","DOI":"10.3354\/dao03073"},{"key":"40","doi-asserted-by":"crossref","unstructured":"KC Prager, MG Buhnerkempe, DJ Greig, et al.  \"PLoS Negl Trop Dis.\"  14, \"Linking longitudinal and cross-sectional biomarker data to understand host-pathogen dynamics: Leptospira in California sea lions (Zalophus californianus) as a case study.\" e0008407 (2020)","DOI":"10.1371\/journal.pntd.0008407"},{"key":"26","doi-asserted-by":"crossref","unstructured":"HJ Holshuh, AE Sherrod, CR Taylor, et al.  \"J Am Vet Med Assoc.\"  187, \"Toxoplasmosis in a feral northern fur seal.\" 1229 (1985)","DOI":"10.2460\/javma.1985.187.11.1229"},{"key":"34","doi-asserted-by":"crossref","unstructured":"M Lynch, O Nielsen, PJ Duignan, et al.  \"J Wildl Dis.\"  47, \"Serologic survey for potential pathogens and assessment of disease risk in Australian fur seals.\" 555 (2011)","DOI":"10.7589\/0090-3558-47.3.555"},{"key":"25","doi-asserted-by":"crossref","unstructured":"FM Gulland, M Koski, LJ Lowenstine, et al.  \"J Wildl Dis.\"  32, \"Leptospirosis in California sea lions (Zalophus californianus) stranded along the central California coast, 1981\u20131994.\" 572 (1996)","DOI":"10.7589\/0090-3558-32.4.572"},{"key":"38","doi-asserted-by":"crossref","unstructured":"MA Miller, WA Miller, PA Conrad, et al.  \"Int J Parasitol.\"  38, \"Type X Toxoplasma gondii in a wild mussel and terrestrial carnivores from coastal California: New linkages between terrestrial mammals, runoff and toxoplasmosis of sea otters.\" 1319 (2008)","DOI":"10.1016\/j.ijpara.2008.02.005"},{"key":"35","doi-asserted-by":"crossref","unstructured":"MA Miller, PA Conrad, M Harris, et al.  \"Vet Parasitol.\"  172, \"A protozoal-associated epizootic impacting marine wildlife: Mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection.\" 183 (2010)","DOI":"10.1016\/j.vetpar.2010.05.019"},{"key":"18","unstructured":"JP. Dubey,  \"Toxoplasmosis of animals and humans.\"  313 (2010)"},{"key":"16","doi-asserted-by":"crossref","unstructured":"MA Delaney, KM Colegrove, TR Spraker, et al.  \"J Wildl Dis.\"  50, \"Isolation of Leptospira from a phocid: acute renal failure and mortality from leptospirosis in rehabilitated northern elephant seals (Mirounga angustirostris), California, USA.\" 621 (2014)","DOI":"10.7589\/2013-08-195"},{"key":"9","doi-asserted-by":"crossref","unstructured":"A Barratclough, SH Ferguson, C Lydersen, et al.  \"Pathogens.\"  12, \"A review of circumpolar Arctic marine mammal health\u2014A call to action in a time of rapid environmental change.\" 937 (2023)","DOI":"10.3390\/pathogens12070937"},{"key":"29","doi-asserted-by":"crossref","unstructured":"CK Johnson, MT Tinker, JA Estes, et al.  \"Proc Natl Acad Sci U S A.\"  106, \"Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system.\" 2242 (2009)","DOI":"10.1073\/pnas.0806449106"},{"key":"8","doi-asserted-by":"crossref","unstructured":"L Barbosa, CK Johnson, DM Lambourn, et al.  \"Int J Parasitol.\"  45, \"A novel Sarcocystis neurona genotype XIII is associated with severe encephalitis in an unexpectedly broad range of marine mammals from the northeastern Pacific Ocean.\" 595 (2015)","DOI":"10.1016\/j.ijpara.2015.02.013"},{"key":"13","doi-asserted-by":"crossref","unstructured":"JR Cole, CR Sulzer, AR Pursell,  \"Appl Microbiol.\"  25, \"Improved micro-technique for the leptospiral microscopic agglutination test.\" 976 (1973)","DOI":"10.1128\/am.25.6.976-980.1973"},{"key":"10","doi-asserted-by":"crossref","unstructured":"KA Burek, FMD Gulland, G Sheffield, et al.  \"J Wildl Dis.\"  41, \"Infectious disease and the decline of Steller sea lions (Eumetopias jubatus) in Alaska, USA: insights from serologic data.\" 512 (2005)","DOI":"10.7589\/0090-3558-41.3.512"},{"key":"11","doi-asserted-by":"crossref","unstructured":"D Carlson-Bremer, KM Colegrove, FMD Gulland, et al.  \"J Wildl Dis.\"  51, \"Epidemiology and pathology of Toxoplasma gondii in free-ranging California sea lions (Zalophus californianus).\" 362 (2015)","DOI":"10.7589\/2014-08-205"},{"key":"41","unstructured":"\"R: A Language and Environment for Statistical Computing.\"  (2023)"}],"container-title":["Journal of Wildlife Diseases"],"original-title":[],"deposited":{"date-parts":[[2026,11,4]],"date-time":"2026-11-04T04:07:57Z","timestamp":1793765277000},"score":1,"resource":{"primary":{"URL":"https:\/\/bioone.org\/journals\/journal-of-wildlife-diseases\/volume-62\/issue-4\/JWD-D-25-00167\/SEROLOGIC-INVESTIGATION-OF-LEPTOSPIRA-SPP-SARCOCYSTIS-NEURONA-AND-TOXOPLASMA-GONDII\/10.7589\/JWD-D-25-00167.full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,11,4]]},"references-count":52,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,10,1]]}},"URL":"https:\/\/doi.org\/10.7589\/jwd-d-25-00167","relation":{},"ISSN":["0090-3558","1943-3700"],"issn-type":[{"value":"0090-3558","type":"print"},{"value":"1943-3700","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,11,4]]}}}